import urllib
from selenium import webdriver
url='http://flight.qunar.com/site/oneway_list.htm?'

params = urllib.urlencode({'searchDepartureAirport': '上海', 
                           'searchArrivalAirport': '西宁', 
                           'searchDepartureTime': '2011-09-16',
                           'searchType': 'OneWayFlight',
                           })
s='上海'
print s.decode('utf-8')